How to Troubleshoot the Climate Control

How to Check for DTCs with the HDS


1.Make sure the ignition switch is OFF.

2.Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.

 

3.Turn the ignition switch ON (II).

4.Make sure the HDS communicates with the vehicle and the climate control unit. If it doesn't, troubleshoot the DLC circuit, except K20Z2 engine, K20Z2 engine.

5.Select HVAC/CLIMATE CONTROL in the BODY ELECTRICAL menu.

6.Select DTCs in the HVAC/CLIMATE CONTROL menu.

7.Check for DTCs. If any DTCs are indicated, write down the DTCs, then go to the indicated DTC troubleshooting. If no DTCs are indicated, refer to symptom troubleshooting.

NOTE:
  • After troubleshooting, clear the DTCs with the HDS.
  • For specific operations, refer to the user's manual that came with the HDS.

How to Use the Self-diagnostic Function with the HDS


1.Make sure the ignition switch is OFF.

2.Connect the HDS to the data link connector (DLC).

3.Turn the ignition switch ON (II).

4.Make sure the HDS communicates with the vehicle and the climate control unit. If it doesn't, troubleshoot the DLC circuit, except K20Z2 engine, K20Z2 engine.

5.Select HVAC/CLIMATE CONTROL in the BODY ELECTRICAL menu.

6.Select INSPECTION in the HVAC/CLIMATE CONTROL menu.

7.Select CLIMATE CONTROL SELF TEST in the INSPECTION menu.

8.Check for DTCs. If any DTCs are indicated, write down the DTCs, then go to the indicated DTC troubleshooting.

NOTE:
  • After troubleshooting, clear the DTCs with the HDS.
  • For specific operations, refer to the user's manual that came with the HDS.

How to Use the Self-diagnostic Function without the HDS


The climate control unit has a self-diagnostic function. To run the self-diagnostic function, do the following:

1.Turn the ignition switch OFF.

2.Press and hold the AUTO and recirculation buttons, and turn the ignition switch ON (II).

3.ALL LCD segments turn on for 2 seconds, then self-diagnostic function begins.

NOTE:
  • The blower motor will run at any speed regardless of what the panel is displaying.
  • If there is any problem in the system, the temperature indicator will light up the segment (A through P) and AUTO indicator corresponding to the error. The temperature indicator will then alternate every second between displaying ‘‘88'' (all segments lit) and the error code segment (A through P) and AUTO indicator. To determine the meaning of the DTC, refer to checking for DTCs.
  • If there are no problems detected, the segments will not illuminate, and the system will appear to be turned off.

 


Clear the DTCs


1.Turn the ignition switch OFF.

2.Press and hold the AUTO and windshield defrost buttons, turn the ignition switch ON (II).

3.Windshield defrost indicator blinks for 5 seconds, then DTCs clear.

Checking for DTCs


The temperature display indicates single or multiple DTCs. If indicator segments A, C, E, G, J, M, and AUTO are on at the same time, there may be an open in the common ground wire. If no DTCs are present, the indicator remains blank.

 

DTC (Temperature Indicator Segment and AUTO Indicator) Detection Item 
An open in the in-car temperature sensor circuit 
A short in the in-car temperature sensor circuit 
An open in the outside air temperature sensor circuit 
A short in the outside air temperature sensor circuit 
An open in the sunlight sensor circuit 
A short in the sunlight sensor circuit 
An open in the evaporator temperature sensor circuit 
A short in the evaporator temperature sensor circuit 
An open in the air mix control motor circuit 
A short in the air mix control motor circuit 
A problem in the air mix control linkage, door, or motor 
An open or short in the mode control motor circuit 
A problem in the mode control linkage, doors, or motor 
A problem in the blower motor circuit 
A and AUTO An open in the recirculation control motor circuit 
B and AUTO A problem in the recirculation control linkage, door, or motor 
C and AUTO Climate control unit internal error 
D and AUTO Climate control unit lost communication with gauge control module (ILLUMI message) 
E and AUTO A short in the recirculation control motor circuit 
F and AUTO Climate control unit lost communication with gauge control module (ECT message) 
J and AUTO Climate control unit lost communication with gauge control module (VSP message) 
K and AUTO Communication bus line error 
L and AUTO Climate control unit lost communication with gauge control module (NE message) 

Displaying Sensor Inputs at the Climate Control Unit


The climate control unit has a mode that displays sensor inputs it receives. This mode shows you what the climate control unit is receiving from each of the sensors, one at a time, and it can help you determine if a sensor is faulty.

Check these items before using the sensor input display mode


1.Turn the ignition switch ON (II), and check the recirculation door function; press the recirculation button to switch from FRESH to RECIRC. The air volume and sound should change slightly.

2.Set the temperature control knob to the desired test temperature. When selecting the test temperature, note these items:

  • ‘‘Lo'' temperature setting will default to MAX COOL, VENT, and RECIRC.
  • ‘‘Hi'' temperature setting will default to MAX HOT, FLOOR, and FRESH.
  • 19 through 31 °C settings will use the automatic climate control logic.

3.Turn the ignition switch OFF.

To run the sensor input display mode, follow these steps


1.Turn the ignition switch OFF.

2.Press and hold both the AUTO and MODE buttons, then start the engine.

3.After the engine starts, release both buttons. The display panel control unit will flash the sensor number and then the value for that sensor. Record the value displayed.

4.To advance to the next sensor, press the A/C button.

Sensor Item Displayed Value 
Mode Positioning BIT 
In-car Temperature °C 
Outside Air Temperature °C 
Solar Radiation Sensor Value: Dark = 00, Flashlight = 04, Cloudy =10, Sunny =65 10 kcal/m2·h 
Evaporator Outlet Air Temperature °C 
Air Mix Opening (Low value indicates cooler air distribution, higher value indicates warmer air distribution) % of opening 
Recirculation Opening % of opening 
Vehicle Speed (Vehicle must be driven to display speed) km/h 
Engine Coolant Temperature °C 
Vent Temperature Air Out (TAO) °C 

NOTE:
  • The sensor values will be displayed in degrees Celsius (°C) or an alphanumeric code. Use the chart to convert the value to degrees Fahrenheit (°F).
  • If the sensor value displays ‘‘Er'' this indicates there is an open or short in the circuit or sensor. Check for DTCs using the HDS, or refer to checking DTCs by DTC indication to check for DTCs.
  • If necessary, compare the sensor input display to an alike, known-good vehicle under the same test conditions.
  • If the sensor is out of the normal range, refer to the sensor test or substitute a known-good sensor, and recheck.

5.To cancel the sensor input display mode, press the AUTO button or turn the ignition switch OFF.

Celsius to Fahrenheit Conversion Table
°C °F °C °F °C °F °C °F °C °F 
32 10 50 20 68 30 86 40 104 
34 11 52 21 70 31 88 41 106 
36 12 54 22 72 32 90 42 108 
37 13 55 23 73 33 91 43 109 
39 14 57 24 75 34 93 44 111 
41 15 59 25 77 35 95 45 113 
43 16 61 26 79 36 97 46 115 
45 17 63 27 81 37 99 47 117 
46 18 64 28 82 38 100 48 118 
48 19 66 29 84 39 102 49 120 

°C °F °C °F °C °F °C °F °C °F 
50 122 60 140 70 158 80 176 90 194 
51 124 61 142 71 160 81 178 91 196 
52 126 62 144 72 162 82 180 92 198 
53 127 63 145 73 163 83 181 93 199 
54 128 64 147 74 165 84 183 94 201 
55 131 65 149 75 167 85 185 95 203 
56 133 66 151 76 169 86 187 96 205 
57 135 67 152 77 170 87 188 97 207 
58 136 68 154 78 172 88 190 98 208 
59 139 69 158 79 174 89 192 99 210 

Alphanumeric Conversion Table
Display Reading
(Alphanumeric) 
°C °F 
A1 thru A9 -1 thru -9 30 thru 16 -1 thru -9 
B0 thru B9 -10 thru -19   14 thru -2 -10 thru -19 
C0 thru C9 -20 thru -29  -4 thru -20 -20 thru -29 
D0 thru D9 -30 thru -39 -22 thru -38 -30 thru -39 
E0 thru E9 -40 thru -49 -40 thru -58 -40 thru -49 
F0 thru F9 ——— ——— +100 thru +109 

Alphanumeric Conversion Table (Mode Positioning)
Display Reading
(Alphanumeric) 
Mode Position 
OVER VENT 
VENT 
VENT-HEAT/VENT 
HEAT/VENT 
HEAT/VENT-VENT 
HEAT 
HEAT-HEAT/DEF 
HEAT/DEF 
HEAT/DEF-DEF 
DEF 
OVER DEF